Heathcliff and the Catillac Cats (1984)

S1E55 Heathcliff Pumps Iron

A powerful, brawny cat named Pecs makes a play for Sonja, prompting Heathcliff to hit the gym and bulk up in a bid to outlift Pecs. However, the gym manager is secretly aligned with Pecs, setting traps to sabotage Heathcliff's efforts. Undeterred, Heathcliff quickly figures out the scheme and counters every obstacle thrown his way. In the end, his determination pays off, and Sonja is won back by Heathcliff.